Pneumatic elevator



. ford a length of stroke-equal to the required uniform pressure'is maintained and aservice conducting off the exhaust-.during the return' system of relatively smallpassages and be .erating freight and passenger' elevators in lthrough an elongated leader in ythe cylinder vis connected to or forms a prolongation of the UNITED STATES PATENTy OFFICE-f.

GEORGE MILES,'OF WELLESLEY, MASSACHUSETTS.

PNEUMATIO unav/trim.v

sP'ncmcATIoN forming part of Letters lamentare-194,211.7, dated Mailen 28, i893.. s i

Application tiled December 4, 1891. Serial No. 413,972. (No model.) l

To all whom it may concern:

Be it known that I, GEORGE MILES, of 'Wellesley,` Massachusetts, have invented a certain Improvement in Pneumatic Elevators, of which the following is a specification.

It is the object of these improvements to facilitate the use of compressed air for opbuildings. .l To this end there is employedf-tf First, a single acting piston reciprocating in a cylinder long enough to afford room for cushioning the piston at both ends and to aflength of travel of the elevator. Secondly, a iiexible piston connector which is loosely run head, and connected to the piston andwhich elevator suspender rope. Thirdly, a compressed air reservoir in which a substantially pipe for supplying compressed air therefrom. Fourthly, a conducting pipe for conducting compressed airinto one end of the cylinder to effect the direct stroke'of the piston andfor stroke of the piston. Fifthly, a three way valve for shutting off the service pipe and e'stablishing a connection between said conducting pipe and an exhaust outlet to permit the return stroke of the piston and for disestablishing the connection-between said conductingpipe and .exhaust outlet and opening a connection between said conducting pipe and service pipe to supply compressed air for eecting the direct stroke of the piston. Sixthly, a bleed valve for admitting into the cylinder a supply of compressed air sufficient. to compensate for the leakage therefrom and maintain upon the-piston just enough pressure to counterbalance the Weight of the elevator and'thereby permit the elevator to be held stationaryy at any desired stage of its upward or'downward excursion. The said bleed valve maybe an independent valve with independent operating devices, or the said three- Way valve may be provided with an especial thus adapted to. itself act as a bleed valve when made to occupy a A prescribed Aposition diierent from either of the positions which it occupies when performing, as hereinbefore stat-ed, its principal functions. Seventhly, au

adjustable valve for regulating the cross area of a passage, whichaftords during the ldirect stroke an rair outletfrom, and duringthe return stroke an airinlet into, the interior of the cylinder at a point justV abo'vethat portion of the extreme lower end of the cylinder which serves as a dash pot for containing the air whiehfcushions the piston at the en d of its direct stroke.' Eighthly, a check valve openinginwardly into the lower end of vthe cylinder to admit air therein, if required, when the piston starts upon its return stroke.

Xlyhile all of the enumerated devices may be usefully assembled and employed in the `same elevator apparatus, it is also the fact that many of thempossessindependently valuable features adapting less than the Whole number of them to enter into various combinations productive of novel and advantageous results. Y Thu'sthey permit the use for operat' ing the elevator, of' a fluid .under pressure, to t wit, compressed air, the leakage, or discharge of which from the cylinder into the elevator well is unattended with any disagreeable eects such as would necessarily attend the similarleakage or discharge of steam or Water from the-cylinder. y

p It results from the .elasticity of the compressed air thatthe elevator is start-ed or brought to rest Without the shock which usually attends the stopping or starting of a water driveny elevator. This does away with the discomfort which. such shocks inflict upon the elevator passengers and vwith the wear and tear upon the apparatus incident to such shocks.

As the leakage of compressed air produces no unpleasant effects itis not necessary to employ a stuing box 'for tightly packing the 4pistou connector in the cylinder head. By merely elongatingthe tubular part of the cylinder head through which the piston connector s'led, the leakage is reduced to a neg; ligible quantity without subjecting' the piston connector tothe friction which the ordinary stuiing box would exert upon it.

' It has heretofore been proposed to employ in the vorganization of steam or water driven elevators, a flexible piston connector, and to -make such flexiblev piston connector a prolongation of the elevator suspender rope,

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and to make the 'stroke of the piston equal to the range of motion of the elevator. It will therefore be'understood that the present invention embraces improvements adapting such an organization for operation by compressed air and secures the advantages re-` sulting therefrom'.

Vfhile it is preferred to use al single acting piston' having a Vstroke equal to the range of movement of a vertically moving elevator in order to thereby lessen the degree of pressure required to eli'ect. the direct stroke of 4 the piston, and to utilize the force of gravity acting upon the elevator to effect the return stroke'of the piston, it is to be observed that the common multiplying gear may be usedin the ordinary' manner to transmit power to or from the elevator from or to a piston havinga shorter stroke but operated by compressed air of higher pressure,without departing from the present invention.

These improvements, so far as regards the organization of the pneumatic hoisting apparatus, are applicable not only to passenger elevators, but to freight elevators orhoists of any kind; therefore the term elevator car, herein used is to be taken as compreh'ending a freight platform or any other device combined with the suspender rope for facilitatingy the suspension thereon of any heavy object which itis desired to elevate. It is also to be understood that the Aterni compressed air service pipe hereinemployed is to be taken as compreheuding any form of conduit, passage, or chamber which is in limmediate connection with the valve for controlling the operation of the elevator, and similarly, that the expression conducting pipe is to be taken as comprehending any forni of conduit, pas' sage, or chamber connecting the cylinder with v the said valve, and finally that the cylinder need not necessarily be upright.

The accompanying drawings, illustrating the application of the improvements to a pas,

senger elevator operated by vcompressed air, are as follows:

Figure 1 isa view, partly in section, of an elevator well, a passenger car, a cylinder and piston, a exible piston connector led over a guide pulley, and formed integrally with the elevator suspender rope, together with a symbolic representation of a'compressed air reservoir, a steam driven air pump, a governor for automatically increasing the speed of the air-pump when the pressure in the reservoir falls, suitable pipe' connections for supplying compressed air to the cylinder, a three way valve -for controlling suoli suppl-y andalso controlling the outlet for the exhaust Afrom the upper end of said cylinder, and an actuating valve rope extending through said passenger car. Fig. 2 isa view, partly in section, of the three way Yvalve,`its connections, and operating mechanism showing the three way valve in its lowest position which it occupies when aiordinga full Supply of compressed air for effecting the downward stroke of the piston, and the consequent upward excursion of the' elevator car. Fig. 3 isa section similar to Fig. 2,'except that it shows the three way valve in its highest position which itoccupies when' completely shutting olf the compressed air and opening 'the outlet for the escape of air from the upper end of the cylinder during the downward excursion of the car.

Fig. 4t is asimilar section of the three way valveshowing it in its middle position which it oc'- cupies'when closingthe exhaust outlet and admitting into the upper end of the cylinder of the upper cylinder head, illustrating thel provision of a multiplicity of elongated leaders for admitting a multiplicity of elevator suspender ropes into the interior of the cylin'-A der for connection' with the piston'. Fig.'7 is a vertical section of the upper end of the cylinder, and of the pipes connected therewith, I

showing the piston at the end of its upward stroke, andshowing the check valve for admitting compressed air into the upper end ofl the cylinder to'initiate the downward stroke of the piston. 4-

. In the drawings a passenger car, A, is represented as adapted to be reciprocated between the vertical guides, A `A, established within an elevator well. The passenger car is hung upon the suspender rope,-B, which is led over a guide pulley, B, and into the upper end of the. vertical cylinder, C, andl fastened to thepiston, D; the suspender rope thus serves as a flexible piston connector. The upper end of the cylinder is closed by a head, C', provided with a-tubnlar extension, C2, which serves as an elongated leader for the end portion ofthe suspender rcpe B which constitutes the iexible piston connector, B2.

The iexible piston connector loosely ts the' elongated leader; but in consequence of the elongation of the leader, the leakage `through it is so small as to be negligible. A

When ropes, either wire ropes or ropes made of vegetable fiber, are employed as piston connectorsit is preferred to cover with grease those portions of the ropes which in operation are drawn-through the elongated leaders.

When this is done, even if airv of high pressure is employed, leakage'from. the cylinder through the elongated -leader will not be observable.I

If, owing to the weight of the elevator car, it is found desirable to em'ploy a multiplicity of suspender ropes, the upper cylinder. head will be provided with a number of elongated leaders, equal tothe number of suspender ropes employed,v and the number of guide pulleys, or the number of grooves in a single guide pulley will be correspondingly in- I creased. Fig. v6, for example, illustrates the.l

' *chamber C5, to, if necessary, admit external use f' the three elongated leaders, permit ting ot the suspender ropes to be led into the inzcar when an outlet is established for the es- `the air is permitted to be expelled through the rapidity -wilh which air is admitted into the lower part of the 'cylinder through the three flexible piston connectors or extensions terior of the cylinder for connection with the piston. For the purposes ot' the present case, therefore, it will be understood that the terms suspender rope and flexible piston connector are tov be taken as comprehending either a single suspender rope, or a single flexible piston connector, or a multiplicity of the same, as the case may be.

At aprescribed short distance aboveits closed lower endthe cylinder is provided with a passage, C3, equipped withavalve, C, for electing a connection between the lower portion of the cylinder and the external atmosphere. J ust vbefore the conclusion of -its downward stroke the piston passes across and closes the inner end of the passage O3. The space within the cylinder below thel level of the passsge, C3, constitutes an air cushion chamber, C5, and the cylinder is so proportioned in length with relation to the range of Imovement of the elevator-.car that the air in the extreme lower end of the cylinder will serve to cushion the piston at the completion of its downward or direct stroke when the elevator car has been carried up to its highest position.4 The direct stroke ofthe piston is eiected by the-introduction of compressed air into the upper end-of the cylinder. Its return stroke is `.caused by the gravity of the cape of the air from the upper end of the cylinder.

For abundant caution there is provided a check valve C, opening into the air cushion air into the cushion chamber afteif the piston has commenced its upward `or .return stroke and until it has risen far enouglLto reopen the passage C3.

-The speed of movement of the piston during its direct stroke' is to some extent inhuenced by the degree .of freedom with which the passage, C, and the valve, C4, and simi-r` larly, the speed of the return or upward stroke of the piston is to some extent influenced by valve, C", the area of the' check valve being purposely made small inonder. that the main supply of air into the lower part of the cylinder during the upward stroke of the piston shall be through the valve,- C4. It therefore follows that by varying the cross area of the passage, C?, by means of the valve, C, the speed of movement ofthe piston, andv conseqnentLy of the elevator may be to some extent regulated. A little below'its upper end the cylinder is connected with a conducting pipe, E, which serves as theinduction passage v for admitting compressedair to eiect the cliv rect stroke of the piston, andalso serves as the eductlon passage through which air is expelled from the upper end of the cylinder during the upward stroke of thepiston. A small tube, e, provided with a check valve, e', inserted into the upper end of the cylinder, or into the upper cylinder head, as shown, and vconnected outside the cylinder with the conducting pipe, E, serves as the inlet into that portion of the upper end of the cylinder which is above its point of connection with the mouth of the conducting pipe, E, the said portion constituting the cushion chamber, e2, for cushioning the piston at the endof its upward stroke after itV has passed across and closed the mouth of the pipe, E. It will be seen thatwhen it is desired to eect the downward stroke of the piston the tube, e, serves as the duct for admitting sufficient compressed air into the cushion chamber, e2, at the upper end of the cylinder to initiate 'the downward stroke and drive the piston past the mouth of the pipe, E, through' which theA main supply of compressed air is furnished for-the downward stroke.- The check valve, e', under the in-v luence of its spring, closes when the supply of compressed air is cutoff, and, as will be perceived on reference to Fig. 7, the check valve, e', prevents the escape of air from the cushion chamber, e2, during the upward movement ofthe piston. lVhen the compressed air is let into the conducting pipe, E, to eect the downward stroke ofthe piston, the check valve yields and allows the compressed air to make its way through the pipe, e, into the cushion chamber, e2.

To enable the conducting pipe, E, to thus serve alternately as the-induction andas the eduction passage, itis alternatelyconnected by. means of the three way valve F, with the compressed air service pipe, G, and 'with' the exhaust outlet, F. The three way valve which it is preferred to employ is substantially like thatshown and described in United IOO States Letters Patent No. l =61,981, granted to me, October 27, 1-891. lThe said valve consists of a valve shell, F2, containing the valve chamber, a, the wall of which is piercedwith the two parallel ports, b and c.v The port, b,

Iopens into the jacket compartment, b', extending around the upper portion o'f the valve chamber and communicating with a nozzle, b2,

.which is tapped at its mouth for connection with the compressed air service pipe,G. The port; c, opens into the jacket compartment, c',

communicating with a nozzle, c2, .which is IIO tapped at its mouth for connection with the y conducting pipe, E. The lower open'end of the valve chamber, a, opensinto the compartment, d, communicating with -the' nozzle, d',

which itself may serve as the exhaust outlet, or may be tapped and connected with a pipe through which the exhaust fromv the upper end of the cylinder is discharged. At its upper end the valve chamber, a, is providedl with theusuallperforated cap through which thevalve stem, f, extends. The valve stem, f, is alixed-to, or formed integrally with,-rthe `hollow cylindrical valve, g, closedl at its ends, and having its curved wall. pertoratedby two parallel rows of holes, hand The upper end of the valve stem, f, has the usual pivotal connection with the4 valve operatingilever, j,

As will be seen on reference to Fig. 2, when the three way vvalve and its operating lever are in their lowest positions the ports, 11 and c, are open, and unconstricted communication is thus established for the supply of compressed air from the compressed air service pipe, G, to the conducting pipe, E.

On reference to Fig. 3 it will be seen that when the three wayvalve and its operating lever are in their highestpositions, the port, I), is closed, thus completely shutting oft communication with the compressed air service pipe, G, while the port, c, is open andin communication with the chamber, (l, and exhaust outlet, d. v l

On reference to Fig. 4, it will be seen that the valve and its operating lever occupy a middle, or intermediate position in which the valve serves'as a bleed valve, by virtue of 'the' fact that the lower' extremities of the ports, h and fi, respectively, occupy positions slightly below the upper edges of the ports, b and c, thus partially opening communication from the compressed air service pipe, G, tothe conducting pipe, E, and admitting into the conducting pipe, E,a comparatively small supply of compressed air, the object of which is to compensate for the leakage from the cylinder and to maintain upon the piston just venough pressure to counterbalance the weight -of the elevator ear. During the upward excursion of the elevator, the upper part ot the cylinder is filled with compressed air, hence the elevator canA be stopped and. momentarily Iheld stationary by raising the valve to an intermediate position, in which it completely closes the ports, b and c, and it' it then be desired to hold the elevator stationary for any considerable period of time, a comparatively smallopeningofthe valve passages will admit sufficient compressed air for that purpose. On the other hand, during the descent of the elevator, owing to the comparatively uncompressed condition of the air in the upper end of the cylinder, it will be necessary to open thevalve ports wider and thusintroduce a larger quantity of compressed-air into the cylinder in order to vestablish sucient pressure'therein to counterbalance the weight of the elevator. It is also to be observed that differences of load upon the elevator car necessarily involve corresponding differences in the quantity of -air required to be introduced Iinto the upper end of the cylinder to counterbalance the weight o f the car.

1 To adapt the three way valve for operation as a bleed valve,'its,apertures, h and z', instead ot' having a circular form, as they are represented in Letters Patent of the United States, No. 461,981, hereinbefore referred to, are provided upon their under sides with the notches or slots, h and 1", in order that the rate of variations in the areas of the'valve openings caused by' the movements of the valve may be rendered more gradual than when the holes, 7L and i', are circular.- This adapts the' three way valve for use as an adjustable bleed valve, and enablesthe operator to easily vary the quantity of' air introduced into the upper end of the cylinder to Vconstitutes one side of an endless rope which is led over the stationary sheavef, at the top of the elevator well and around the stationary sheave,j3, at the bottom of the elevator well. 'lhe rope,7", extends through leaders, j* and (i5, respectively, at the top and bottom of the ear and through the interior of the car in convenient position to be grasped bythe operator within the car. The part of the rope', j', near its point of'connection with the lever, j, is provided with a fixed collar, jf'. As the car nears the end of its upward excursion the collision of the leader j* with the collar, j, Araises the valve, g, to an intermediate position in which it shuts olf, or nearly shuts off, the communication between the compressed air service pipe, G,.and the conducting pipe, E.. Near the lower sheave the rope, `7", is provided with another fixed collanj?, so that by they col` lision therewith of the leader, j, near'the'end of the downward excursion of the elevator car the valve, g, will be lowered to an intermediate position, in which it disestablishes the com- .ward excursion, is to temporarily communicate the motion of the ear to the valve rope, j. This is conveniently effected by means ot a manually operative yielding clamp, such,

for example, as that illustrated in Fig. 5, which consists of the bell cranklever, k, the longer arm of which is provided with'the handle, it', and which is so pivoted tothe wall of the el evatorcar that its shorter arm, k2, engagesl a transverse pin in the clamping bolt, lo?. Down- Ward .pressure upon the handle, k', imparts endwise motion to the-bolt, k3, compressing the spring, 7a4, and driving the movable grooved jaw, les, against the rope, j', whereby the-rope, j', is clamped against the stationary grooved jaw, k6, affixed to the wall of the elevator. YVhen the handle, lc', is released from downward pressure the spring, 164, pushes back the clamping bolt and releases the rope, j.- By a little practice the operator will learn how to more orlessquicklyrelease the handle, k', after having pressed it downward to clamp the rope and be thereby enabled to move the valve to IOO munication theretot'ore existing betweeny the its desired intermediate position and bring the elevator car to rest at any stage of its movement in either direction.

To start the car upward at'ter Ait has been brought 'to rest the operator will pull the rope, y', downward so as to lowei` the valve,'g, to the position in which it fully opens communication between the compressed` air service pipe, G, and the conducting pipe, E. To start Athe car downward, the operator will pull the rope, j', upward sufficiently to raise the valve,

g, to the position in which it shuts 0E the compressed air vand opens communication ybetween the conducting pipe, E, and the exhaust outlet, d.

It isimportant for the successfuioperation of the apparatus that a substantially constant pressure shall be maintained in' the conipressed air service pipe. Thisis most effectively accomplished by connecting the com.

pressed air service pipe with a reservoir supplied with compressed 'air by an air pump,

the speed of motion of which is variedV by the action of a governor automatically controlled in its operation by the degree oil pressure in the compressed air reservoir. An example of a form of apparatus which can be conveniently used for this purpose is shownand described in Letters Patent of the United States4 ,provided with a flexible connector for connecting its piston with an elevatorcar, is well known in the art, no especial description of it is herein needed. f It will therefore be un derstood that the expression iiprightcyliirder is herein employed simply for convenience, and is not tobe taken as imposing `any limitation concerning theposition of the cylinder. Y What is claimed as the invention is- 1. In a pneumatic elevator apparatusan vupright cylinder having its lower end closed v but provided with an inwardly opening check valve, and having at a prescribed short distance above its lower end, a relief passage opening the adjacent part of its interior to the external atmosphere, in combination with-a piston, an elevator car, connections for connecting said piston with said car, and means for edecting the reciprocation of said piston in said cylinder. V

2. In a pneumatic elevator apparatus, an

' upright cylinder closed at its lower end and having at a prescribed short distance .above its lower end a relief passage opening the adf jacent-part of its interior the-'external atmosphere, a piston, an elevator car, connecand means for effecting the reciprocation of with a valve for adiustimgrthe cross areaV of said relief passage and thereby influencing the speed ofmovement of said piston. v

3. In a pneumatic elevator apparatus, an uprightcylinder having an opening through which its lower portion communicates'withthe external atmosphere, a piston, an elevator i tions for connecting said piston with said car:

said piston in said cylinder, in combination? car, connections extending through the cyl..

inder head at the upper end of said cylinder for connecting said pistonwith said car, a conducting pipe for conducting compressed air into the upper end of said cylinder to eect the direct strokeof said piston andfor con.- diicting oi the exhaust during the return stroke of said piston, and a compressed air service pipe; in combination with valve mechanism for alternatelyconnecting said conducting pipe with said service pipe to supply compressed air for effecting the direct, stroke of said piston 'and for connecting said conductescape of the air expelled from the upper end of said cylinder during the return stroke l of said piston.

4. In a pneumatic elevator apparatus, the combination'as herein s et forth of an upright 'ing pipe with an exhaust outlet to permit the cylinder, a -pistoii reciprocating therein, an

elongated tubular head at the upper endot -said. cylinder, an elevatorcar, a suspender rope therefor, a flexible piston connector led loosely throughsaid elongated tubular head IDG and connected with said piston and connected with 'or forming a prolongation of said suspender rope and ineansfor supplyingcom.-y pressed a-ir to the upper end of said cylinder to eiect the direct stroke of saidpiston and for shutting oitthe supply of compressed air and 'openingen outlet for the escape of the fair from'the upper end of said cylinder to per-v mit the return stroke of said piston.

5. In a pneumatic elevator apparatus, the Vcombination as herein set forth of a cylinder,

a piston reciprocating therein, an elevator car,

connections for connectingsaid piston with said elevator car, a compressed air service pipe, a conducting pipe for conducting conipressed yair to `said cylinder to effect the direct stroke of said'piston, a valve mechanism f for opening or closing a connection between said 'service pipe and said conducting. pi-pe,

-and means for maintaining-fthe' ,compressed air in said service pipe at a substantially conz stant degree of pressure.

6. In a pneumatic elevator apparatusf'the'.

combination as herein set forth of a cylinder, a-piston reciprocating therein, aiielevator car, connections for connecting said piston with said elevator car, afcompressed vair servicel pipe, aicondiicting pipe for conducting vcompressed air to `said cylinder to effect the direct stroke of said piston, and a bleed valve for admitting from said compressed air servi f ice pipe in'to said conducting pipe and thence into said cylinder, a supply of compressed connected with the side of said cylinder 'at a air, enough to compensate for the leakage prescribed distance below its upper-vend; a from said cylinder and to maintain upon said tube inserted into the upper cylinder head, 15 piston suicient pressure to counterbalance and connected outside the cylinder with the 5 the' weight of said elevator car for the pursaid conducting.a pipe and provided'with a pose ofaffordingaconvenient means for holdcheck valve, as shown, as and for the puring'the elevator car stationary at any desired poses set forth. stage init's upward or downwardexcursion.

7. In a pneumatic elevator apparatus, a cyl- GEORGE MILES. 1o inde'rfa piston .reciprocating therein; an elel Witnesses:

vater cargconncctions for connecting said pis- E. GATTERER, ton with said elevator car; aconducting pipe A. M. JONEs. 

